The Dept. of Immunology and Infectious Diseases (DIID) in the Division of Biologic Sciences (DBS) at the Harvard School of Public Health (HSPH) comprises a strong team of accomplished scientists who work on problems related to the immune response and to the biology, epidemiology and immunology of infectious diseases. DBS, established in 1993, is an umbrella structure that encompasses the biologic laboratory sciences in the areas of Immunology and Infectious Diseases, the Genetics of Complex Diseases, Cancer Cell Biology, Environmental Health, and Nutrition. The Ph.D. Program in Biological Sciences in Public Health (BPH) is located at HSPH and is offered by the Graduate School of Arts and Sciences. This predoctoral training grant competitive renewal application would support BPH students who choose to work in laboratories of faculty members of the Department of Immunology and Infectious Diseases. The BPH program provides a unique opportunity for training a cadre of leaders who possess expertise in the individual fields of biological research and a broad interdisciplinary knowledge of epidemiology and biostatistics. It has become increasingly evident that progress in disease prevention is optimally promoted by a close interaction between epidemiologists and laboratory scientists, where laboratory discoveries and epidemiological observations interact in an iterative manner to advance research in both fields. Our training record in this grant period has been excellent as evidenced by the publication record and career paths of the predoctoral students supported. The Dept. can be subdivided into three major areas, Immunology, Molecular Biology of Parasitic and Other Infections, and Virology. Faculty members in these Divisions are the PI, Laurie Glimcher, gene expression in lymphocytes;Barry Bloom, Sarah Fortune and Eric Rubin, tuberculosis;Tiffany Horng, inflammation, Wendy Garrett, host-commensal interactions;Dyann Wirth, malaria, leishmaniasis;Barbara Burleigh, T. cruzi, malaria;Manoj Duraisingh, malaria;Myron Essex, Phyllis Kanki, human immunodeficiency virus. Three faculty members with primary appointments at HMS are Judy Lieberman and Joseph Sodrowski, HIV, l-Cheng Ho, cytokines and Hidde Ploegh, MIT, cell biology of viral infections. RELEVANCE (See instructions): Basic biological and epidemiological discoveries must be placed in a wide social context. This program encourages active collaboration among scientists who share complementary interests in developing closer linkages between laboratory research and field work- all with an eye to developing innovative approaches to prevention. The field of immunology and infectious diseases, and the graduate students in the Department of Immunology and Infectious Diseases at HSPH is ideally suited for this Interaction.